When travelers return home from a vacation, they typically bring cool souvenirs, cherished memories and a broadened perspective on the world. But sometimes they also come home with a terrible cold, digestive problems or other health issues. It’s common to get sick when you travel, whether you come down with symptoms during the trip or start feeling bad after the return. But this outcome doesn’t have to be inevitable. “You can assume that travel will increase the risk of getting sick, and none